Method of making master phonograph records



Patented Mar. 20, 1923.

UNITED STATES PATENT METHOD F MAKING MASTER PHONOGRAPH RECORDS.

Application filed August 10, 1921. Serial No. 491,111.

To all whom, t may Concern Be it known that I, WILLIAM H. COLE,

a citizen of the United States, residing at Newark, in the county ofEssex and State of New Jersey, have invented a certa-in new and usefulMethod of Making Master Phonograph Records, of which the following is aspecification.

The principal object-s of the present invention are` first, to simplifythe processor method of producing master record-s by reducing thenulnberof steps involved; second, to produce an improved and more accuratemaster record; and third, to produce the master record direct from thewax record. Other objects of the invention will appear from thefollowing description and the invention will be pointed out and claimedat'the end hereof.

In the practice of my invention metal is deposited by precipitation fromsolution distributed upon the Wax or like record by the action ofalcohol, and one or more of the same or of different kinds of metal areelectro-plated upon the metal first deposited from solution, so that theremoval of .the wax exposes the metal first deposited from solution, andthis metal exactly and faithfully 'conforms to the grooves in the waxrecord with which it directly contacted; accordingly my inventioncomprises the process above outlined.

In additionally describing the invention reference will be made to theaccompanying r drawings in which- Figures l. 2, 3 and 4.dia-gra-mmatically and schematically represent steps into which theprocess may be divided, and

Fig. 5 similarly .represents the master 40 record.

In connection with the drawings it will be assumed that the face 1,ofthe master record is of silver and that the back 2 of the masterrecord is of copper. The backing as of loaden material usually appliedto the copper 2 is not shown. I will now describe thc manufacture ofsuch a silver faced copper hacked master record by the process of thisinvention.

The wax record 3 is made in the usual or 'in any preferred way. Anammonical silver solution is made` for example. by dissolving silvernitrate i'n aqua ammonia and this solution along with alcohol is appliedto the face of the wax record. From this'solution silver is deposited asat 5 by means of an aldehyde, preferably formaldehyde. The alcohol playsan important part in that it insures proper distribution of the solutionof silver salts over the surface of the wax. This deposit 5 iselectro-plated with a coating or layer of metal 6, in the presentinstance silver, so that the deposit from solution and theelectroplating 6 of silver thereon together constitute a layer ofsilver, and upon this composite layer of silver is electroplated copper7. The finished product is shown in F ig. 5, in which 1 is silver and 2is copper and the exposed face of the silver 1 is the deposit from thesolution, Fig. 2, which was in direct contact with the face 3 of the waxrecord 4, and therefore it faithfully and accurately corresponds withthat face.

The invention being chemical and electrochemical in its nature, Ireserve the benefit of the doctrine of equivalents allowed in suchcases.

I claim:

1. The method of making master records from wax and like records, whichconsists in depositing metal directly onto and in contact with the `faceof the wax record by applying an admixture of a solution of salts of themetal and alcohol to the surfacel of the record and precipitating themetal therefrom, and then electro-depositing metal upon the metal firstdeposited from solution. substantially as described.

2. The method of making master records from wax and like records` whichconsists in depositing silver directly onto and in contact with the faceof the wax record by applying an admixture of alcohol and a solution ofnitrate of silver in aqua ammonia to the face of the wax record andprecipitating silver therefrom by formaldehyde. electroplating silverupon the silver deposited from solution, and electro-plating copper uponthe electro-phtml silver, substantially as described.

3. In the method of making master records from wax and the like theimprovement which consists in depositing metal directly onto and incontact with the surface 0f the wax record by precipitating it from asolution containing alcohol. and then applying additional metal to theback of said deposit which latter becomes the face of the master record,

WILLIAM H. COLE.

